short-segment incremental (SSIS) studies

The short-segment incremental stimulation (SSIS) technique, also called “inching” or “centimetric test”, was first described in the late 1970s, and it consists of applying stimuli at multiple short-distance increments along the course of a nerve. This technique is used to localize an area of focal slowing or a conduction block, and it can be performed using orthodromic or antidromic methods. Following the antidromic method by Kimura (1979), the sensory nerve action potentials ( SNAPs) can be recorded to the digit II (index finger), stimulating the median nerve percutaneously at 12 points between the midpalm and the distal forearm in 1 cm increments.